2010 50hp 2 stroke poor idle

[schr9091]

im working on a 50hp two stroke it sometimes idles fine and then for no reason will just die start it up and will idle fine again so far ive had all carbs off and cleaned all fuel bowls changed the fuel filter ,spark plugs,tried a new gas tank and fresh gas it stil will randomly shut off been reading about cdi box just seems like a lot of money to throw at a guess was thinking about trying the seafoam idea tomorrow....i just am stumped...randomly shuts off and seems to randomly miss fire...any help would be appreciated

[schr9091]

also this motor has about 5 total hours on it since new ..its mounted on a 18 foot pontoon boat

[99yam40]

that new of a motor should have the pilot screws behind some discs keeping non trained people from messing with adjustments to meet EPA guidelines.

Did you remove those and clean all passages and jets?
May need to have the carbs cleaned in a sonic bath and follow the link and sync procedures every time you put carbs back on.

That motor has not even been run long enough to get the rings to seat properly and probably has sat for long periods of time between running.
so clean them properly and run it following break in procedures. Compression test would be a good Idea to see if it is sealing cylinders properly

[dorf]

I had a 2006 with about the same problem......look for a a stuck anti-siphon valve in the fuel tank. The prime -Start thing is also a culprit. My compressions were 115 PSI on each. The link and sync procedure is important. Also check for junk in the OEM filter and fuel lines..

My "new to me" boat had fuel lines that had a coating of ethanol inside the fuel lines and it looked like another small hose inside of the fuel line... with white/yellow scummy stuff all over.????

Just my 2 cents.......

[schr9091]

update

update got it to idle but the only way it will is by me advancing the pointer on the cdi box also my tach reads lower then true rpm i unbolted the cdi and looked behind it there are little white pieces of plastic semi glued to it on the back side ...is that normal or do i have a cdi box that was dropped on the floor during manufacturing i feel like i have a lemon

[99yam40]

It is normal to have some of that on CDI

you can check timing to see if it is meeting spec with a light
at start up timing is advanced a little until motor is warmed up and then drops back to the normal idle timing

You did not say if you pulled the pilot screws when cleaning

[schr9091]

i only cleaned the bowls and they were clean already i also ran the seafoam ****tail changed plugs cleaned the oem filter tried a different tank also the tach dont go pass 3000 rpm even though it sounds like wot the tach is set to 6p i think it mite be a control wiring issue not sure

[99yam40]

my guess is to clean properly and adjust as service manual says

[schr9091]

well got so fed up with it went out and got a brand new 50 four stroke this thing is smooth and lots of power too waiting to hear back from the marina on the 2 stroke but i think its a bad cdi box

[mackwrench]

Where you located? I maybe a player on the 2-stroke, if it's for sale

[TownsendsFJR1300]

idle

The idle passages (and main for that fact) are pretty small and doesn't take much to block up.

Cleaning the bowl is fine, but if the jets are still clogged or partially clogged, it won't run right until their actually cleaned(and you can see light thru them).